1JZ Harmonic Balancer hitting rear cover (now with pics)

[Hybrid]

Agreed. There's a reason it's called a "harmonic balancer" and not just a "pulley".

Don't worry I am sold on the idea of using a genuine one. The goal with my car has always been reliability over power every time.

[love ke70]

harmonic balancer = removes harmonic vibrations in crank yes?
and running a standard pulley (as opposed to harmonic balancer) = harmonic vibrations in the crank = cracked crank
yes?

[Hybrid]

harmonic balancer = removes harmonic vibrations in crank yes?
and running a standard pulley (as opposed to harmonic balancer) = harmonic vibrations in the crank = cracked crank
yes?

Indeed I believe you are on the money from what I have read and understand.

[Hybrid]

FYI guys here is a pic of my engine with the crank pulley back on.

You can still see the rubber section on the outside of it, however is there a rubber section on the back of it that keeps it the required distance from the cover.

It's just seems the belt seems to line up fine.

Sorry I can't remember off the top of my head what it looks like behind without taking it off again.



Pic without pulley on. Seems fine behind it.

[love ke70]

are you sure the timing cover hasnt just pushed itself forwards a bit?

mine did when i threw an oil pump pulley and the nut jammed it forwards a bit...

[Hybrid]

are you sure the timing cover hasnt just pushed itself forwards a bit?

mine did when i threw an oil pump pulley and the nut jammed it forwards a bit...

Nup seems to sit fine. It looks like it has been rubbing for some time. There was rubber bits imbedded in the timing cover from the pulley.

I mean it seems like that is the issue (the pulley rubber is buggered), just trying to make sure I haven't overlooked anything else.

[PlacentaJuan]

harmonic balancer = removes harmonic vibrations in crank yes?
and running a standard pulley (as opposed to harmonic balancer) = harmonic vibrations in the crank = cracked crank
yes?

so the harmonic balancer reduces vibration in the crank or the pulley?

i kind of don't understand how it would reduce and vibration in the crank, because a pissy little pulley wheel that is attached to a rubber serpentine belt surely wouldn't be able to reduce vibration in a big heavy high speed crank attached to 6 pistons would it?

considering the weight of the pulley itself i would have thought that the CRANK would be absorbing vibes from the PULLEY, which means if you have an alloy pulley a fraction of the weight.

standard 1jz crank pulley (+balancer) is a little over 4kg.

the aftermarket alloy underdrive pulley weights 450g.

[love ke70]

reduces HARMONIC vibrations in the crank.
it works. im sure google will tell you how

[love ke70]

http://en.wikipedia.org/wiki/Harmonic_balancer

bam

[PlacentaJuan]

hmm...

joel also pointed me to this article from club4ag.com

Because Toyota balances their engines fairly well, this researcher would rather not categorize the 4A-G pulley as a harmonic balancer. The typical harmonic balancer is constructed such that it has a mechanical means to dampen the rotating, torsional, imbalances caused from loose (poor) manufacturing practices and materials used for the crankshaft, pistons and flywheel. Typical harmonic balancers are hollow inside, either filled with a heavy silicone like substance, used to counter imbalances, or have some other kind of heavy mass. The heavy mass is some times called an inertia ring. This inertia ring is separated by a thin rubber buffer that isolates and absorbs the crankshaft’s natural frequencies and their harmonics. It is a simple rule of physics that states that if the crank stays at its natural resonant frequency (at RPM), those vibrations (harmonics) will add to the destructive forces to eventually break the crankshaft.



The 4A-G pulley appears to be designed to absorb high frequency vibration caused from the optional power steering pump and/or air conditioner when they are turned on, or (though it’s hard to imagine) to isolate these accessories from the engine. The GZ and late model 20v attempted to isolate the crank from all accessories. In both models of pulleys, it is the inside and outside pulley that are isolated from the crank, and in all cases the mark for the ignition reference is not considered a “hard” reference since the rubber isolator could allow the outer rim of the pulley to move or slip from its position.

i guess so then if you had a balanced crankshaft, you wouldnt need the balancer anymore.

[love ke70]

yes you would.
it has to do with the torque applied to the crank by the firing of the cylinders creating vibrations.
not through any imbalance in the crank itself...